1. Field of the Invention
The invention relates to a grommet opening/closing apparatus to pass a wiring harness through a grommet, by expanding a diameter of the grommet having a fitting portion at its both ends which is fitted to an opening of a panel or the like, and a method for passing a wiring harness through the grommet by using the grommet opening/closing apparatus.
2. Description of the Related Art
FIG. 9A and FIG. 9B show one example of a conventional grommet opening/closing apparatus. Structure of the example is shown in Japan Patent published Application No. H5-342928 as of Patent Document 1.
The grommet opening/closing apparatus 41, as shown in FIG. 9A, is also called a grommet stretcher, and includes four pin-shaped hooks 42, four levers 43 each provided with the hook 42 projecting horizontally from a top end portion thereof, gears 44 provided at a base portion of the levers 43, which two gears 44 at two corresponding levers 43 engaging with each other, a pinion 45 engaging with one gear of the other two gears engaging with each other, a rack 46 and an air cylinder 47 to move the rack 46. The rack 46 engages with one gear of the two gears 44 engaging with each other and the pinion 45.
As shown in FIG. 9B, by inserting the hooks 42 inside a waterproof grommet made of synthetic rubber (hereafter called “the grommet”) and moving the rack 46 forward by the cylinder 47, the levers 43 rotate together with pinions 44 and 45, and open the hooks 42 so as to expand the grommet 48. Under this condition, a wiring harness (not shown) is passed through the expanded out grommet 48.
The grommet 48 is formed into a cup-shape and has an opening 49 with a small diameter at one side thereof (or of the grommet 48) and an opening 50 with a large diameter at the other side thereof, and a round groove 51 on an outer surface of the opening 50 to fit into a hole (not shown) of a panel of a car body or the like. When a wiring harness (not shown) with a connector at an end thereof is sealed up and fixed at the opening 49 with small diameter (for example, by reeling up the wiring harness with tape), and the round groove 51 is fitted into the hole of the panel, the hole is waterproofed by the grommet 48.
FIG. 10A and FIG. 10B show another example of a conventional grommet opening/closing apparatus. Structure of the example is shown in Japan Patent published Application H10-233131 as of Patent Publication 2.
This grommet opening/closing apparatus 61 has four pin-shaped hooks 62, movable arms 63, each of the movable arms 63 having a horizontally projected hook 62 fixed on the tip side thereof, links 65 connecting each base side of the movable arms 63, a fixed arm 64 independent from the links 65, an axis 66 holding a intermediate portion of each of the movable arms 63, and a device (not shown) driving each of the links 65 back-and-forth.
Inserting the hooks 62 in a closed condition shown in FIG. 10A into a grommet (not shown) through an opening at a small diameter side thereof, and driving the links 65, as shown in FIG. 10B, so as to open the hooks 62 to expand the small diametric side of the grommet, a wiring harness (not shown) is passed through the grommet. Opening and closing operation of the hooks 62 is done by a worker pressing a footswitch (not shown).